The present invention relates to electrical adapters. More particularly, the present invention pertains to adapters for packaged integrated circuit devices, e.g., ball grid array packages, flip chip packages, etc.
Certain types of integrated circuit packages are becoming increasingly popular due to their occupancy area efficiency. In other words, they occupy less area on a target board on which they are mounted while providing a high density of contact terminals. For example, one such high density package type is a ball grid array package. Generally, ball grid array packages contain an integrated circuit having its die bond pads electrically connected to respective conductive solder spheres that are distributed on the bottom surface of the package in an array. A target printed circuit board typically has formed on its surface a corresponding array of conductive pads which are aligned with the array of solder spheres for electrically mounting the ball grid array package on the target board. The target board typically includes other conductive traces and elements which lead from the array of conductive pads used for mounting the ball grid array package to other circuitry on the board for connecting various components mounted thereon. Typically, to mount such a ball grid array package to a target board, the package is positioned with the array of solder spheres corresponding to the array of conductive pads on the target board. The resulting structure is then heated until the solder spheres are melted and fused to the conductive pads of the target board.
Such area efficient packaging, e.g., ball grid array packages, provide a high density of terminals at a very low cost. Also, this packaging provides for limited lead lengths. The limited lead lengths may reduce the risk of damage to such leads of the package, may provide for higher speed product, etc.
Generally, circuit boards and/or components mounted thereon are tested by designers as the circuit boards are being developed. For example, for a designer to test a circuit board and/or a ball grid array package mounted thereon, the designer must first electrically connect the solder balls on the ball grid array package to the target circuit board. As described above, this generally includes mounting the ball grid array package on the target board and heating the solder spheres to fuse the solder spheres to the conductive pads of the target board. Therefore, the package may be prevented from being used again. It is desirable for various reasons to use package adapters for mounting the packages and reuse ball grid array packages after testing. For example, such ball grid array packages may be relatively expensive. Further, for example, once attached, the solder spheres are not accessible for testing. In addition, it is often difficult to rework the circuit board with the packages soldered thereon.
Various adapters for ball grid array packages which electrically connect a ball grid array package to a target printed circuit board without requiring that the solder balls on the ball grid array package be fused to the target board are known. For example, one such adapter is shown in U.S. Pat. No. 5,892,245 to Hilton, issued Apr. 6, 1999 and entitled, xe2x80x9cBall Grid Array Package Emulator.xe2x80x9d However, the high density of terminals for certain packages, e.g., ball grid array packages, lead to various interconnect problems for adapters being used with such packages. For example, such a high density of terminals, e.g., solder spheres, of such packaged devices may lead to isolation problems between conductive elements of conventional adapters used for connecting the packages to the target board. Further, many adapters require the provision of structure on the target board for mechanically fastening an adapter thereto. For example, in many cases the target board is required to have holes defined therein for receiving fastening devices to mechanically mount the electrical adapter to the target board. Yet further, alignment of the contact terminals of the packaged device, e.g., solder spheres, to the contact pads of the target board may be problematic when an electrical adapter is used.
The present invention provides a packaged device adapter assembly preferably useable for high density integrated circuit packages, e.g., ball grid array packages, flip-chip packages, chip scale packages, etc. An adapter assembly according to the present invention for receiving a packaged device having a plurality of contact elements disposed on the surface thereof includes a perimeter wall member having a length along an adapter axis between a first end of the wall member and a second end of the wall member. A conductive element layer including arranged contact elements, e.g., a conductive elastomer layer or an array of contact elements isolated by insulative material, is positioned at the first end of the perimeter wall member orthogonal to the adapter axis. The perimeter wall member and the conductive element layer define a socket cavity to receive the packaged device. Generally, the plurality of contact elements of the packaged device are adjacent the conductive element layer. A cover member is positioned at the second end of the perimeter wall to close the socket cavity. The cover member is movable to allow the packaged device to be removed from the socket cavity. The adapter apparatus further includes a floating member that is moveable in the socket cavity and an actuator element operable to provide a force on the floating member such that a corresponding force is distributed to the packaged device when the packaged device is received in the socket cavity such that the plurality of contact elements thereof are in electrical contact with the arranged conductive elements.
In one embodiment of the adapter apparatus, the actuator element is associated with the cover member. For example, the actuator element may be a threaded element moveable in a threaded insert of the cover member. Further, the threaded element may include a heat sink head portion with a threaded portion extending therefrom.
In another embodiment of the apparatus, the floating member is a plate member having a surface configured as a function of a surface of the packaged device. The surface of the plate member is positioned in direct contact with the surface of the packaged device when the packaged device is received in the socket cavity.
In yet another embodiment of the apparatus, the perimeter wall member has an inner surface facing towards the adapter axis and an outer surface facing in an opposing direction. The outer surface of the perimeter wall member includes an adhesive retaining surface adjacent the first end thereof. In various embodiments, the adhesive retaining surface may include one or more channels located adjacent the first end of the perimeter wall, an additional adhesive material (e.g., double-sided tape) may be applied on the first end of the perimeter wall member, and the adhesive material applied to the adhesive retaining surface may also be in contact with a target board.
In another embodiment of the apparatus, the apparatus further includes an alignment structure positioned in the socket cavity adjacent the conductive element layer and adjacent the surface of the packaged device on which the plurality of contact elements are disposed to align the contact elements of the packaged device with contact pads on a target board when the adapter apparatus is mounted relative to the target board. For example, the alignment structure may include an alignment plate positioned orthogonal to the adapter axis and may include at least one opening defined therein to allow the contact elements of the packaged device to be in electrical contact with the arranged conductive elements. Yet further, for example, the alignment plate may include a plurality of openings with each opening corresponding to one of the plurality of contact elements disposed on the surface of the packaged device. Yet further, the alignment plate may include an outer surface positioned adjacent the perimeter wall member and an inner surface facing inward towards the adapter axis with the inner surface formed to include arc surface portions corresponding to certain perimeter solder spheres of a ball grid array package received in the socket cavity. In addition, the alignment structure may include a lip portion of the perimeter wall member extending inward towards the adapter axis at the first end of the perimeter wall member.
Another adapter apparatus according to the present invention for receiving a packaged device having a plurality of contact elements disposed on a surface thereof includes a perimeter wall member having a length along an adapter axis between a first end of the wall member and a second end of the wall member. The perimeter wall member has an inner surface facing towards the adapter axis and an outer surface facing in an opposing direction. The outer surface of the perimeter wall member includes an adhesive retaining surface adjacent to the first end thereof. The adapter apparatus further includes a conductive element layer including a plurality of arranged conductive elements positioned at the first end of the perimeter wall member orthogonal to the adapter axis. The perimeter wall member and the conductive element layer define a socket cavity to receive the packaged device with the plurality of contact elements of the packaged device in electrical contact with the arranged conductive elements. A cover member is positioned at the second end of the perimeter wall to close the socket cavity. The cover member is moveable to allow the packaged device to be removed from the socket cavity.
In one embodiment of the adapter apparatus, the adhesive retaining surface includes one or more channels located adjacent the first end of the perimeter wall. In yet another embodiment of the apparatus, an additional adhesive material is applied on the first end of the perimeter wall member, e.g., double-sided tape.
In yet another embodiment of the adapter apparatus, an adhesive material is applied to the adhesive retaining surface such that the adhesive material is also in contact with the target board. For example, the adhesive material may be an epoxy material.
Yet another adapter apparatus is described according to the present invention for receiving a packaged device having a plurality of contact elements disposed on a surface thereof. This adapter apparatus includes a perimeter wall member having a length along an adapter axis between a first end of the wall member and a second end of the wall member. A conductive element layer including arranged conductive elements is positioned at the first end of the perimeter wall member orthogonal to the adapter axis. The perimeter wall member and the conductive element layer define a socket cavity to receive the packaged device with the plurality of contact elements thereof in electrical contact with the arranged conductive elements. A cover member is positioned at the second end of the perimeter wall to close the socket cavity. The cover member is movable to allow the packaged device to be removed from the socket cavity. An alignment structure is further positioned in the socket cavity adjacent the conductive element layer and adjacent the surface of the packaged device on which the plurality of contact elements are disposed. The alignment structure aligns the contact elements of the packaged device with contact pads on a target board when the adapter apparatus is mounted relative to the target board.
In various embodiments of this adapter apparatus, the alignment structure may be an alignment plate positioned orthogonal to the adapter axis between the layer of arranged conductive elements and the surface of the packaged device in which the plurality of contact elements are disposed, the alignment plate may include at least one opening defined therein to allow the contact elements of the packaged device to be in electrical contact with the arranged conductive elements, the alignment plate may include a plurality of openings defined therein with each opening corresponding to one of a plurality of contact elements disposed on the surface of the packaged device, the alignment plate may include an outer surface positioned adjacent the perimeter wall member and an inner surface facing inward towards the adapter axis with the inner surface formed to include arc surface portions corresponding to certain perimeter solder spheres of a ball grid array package mounted in the socket cavity, or the alignment structure may include a lip portion of the perimeter wall member extending inward towards the adapter axis at the first end of the perimeter wall member.